Recently, a semiconductor chip has been required to be mounted in a thin package, such as IC CARD or IC TAG et al., or in a multi chip package in which semiconductor chips are stacked. A semiconductor chip including a metal film formed on a back surface has been required to be thinly processed on a thickness of the semiconductor chip.
Proceeding of miniaturization and high integration of a semiconductor device has been accompanied with an enlargement of semiconductor substrate diameter. The semiconductor substrate is thinned by back surface polishing et al. and is separated to a plurality of semiconductor chips by dicing in processing steps of back surface of the semiconductor substrate. The semiconductor substrate thickness below 100 μm easily causes generation of crack and lack in the substrate at processing and moving in manufacturing steps of the semiconductor device. Japanese Patent Publication (Kokai) No. H10-92778 discloses a method of sticking a protective tape on a thinned semiconductor substrate suppresses generation of crack in the thinned semiconductor substrate at processing and moving in manufacturing steps of the semiconductor device.
On the other hand, the processing steps mentioned above have a several problems on assembling a semiconductor substrate or a semiconductor chip. When the semiconductor substrate with a large diameter has a thickness ranged from a several tens of μms to 90 μm, local stress applied to the semiconductor substrate causes generation of local crack and lack of the semiconductor substrate in processing and moving. Furthermore, in process steps being formed a metal film on a back surface of the thinned semiconductor substrate or the semiconductor chip, enlargement of coupling strength between the back surface and the metal film becomes difficult. Moreover, in process steps fully being cut a thinned semiconductor substrate with a metal film on a back surface by blade-dicing, bending strength of a semiconductor chip becomes smaller so that improvement of reliability on a resin-molded semiconductor device including the semiconductor chip becomes difficult.